Circlip
Retaining Rings & Clips · snap ring · retaining ring · seeger ring
Definition: A circlip is a snap ring that fits in a machined groove to hold parts on a shaft or in a bore — the DIN term for internal and external retaining rings.
Anatomy
■ Ring body■ Opening
Governing standards: DIN 471 (external) · DIN 472 (internal) · ASME B18.27
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| shaft/bore 1/4 | 6 mm | — | — |
| shaft/bore 1/2 | 12 mm | — | — |
| shaft/bore 1 | 25 mm | — | — |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Spring steel | spring steel | — | None |
| Stainless / phosphor bronze | varies | — | None |
Materials
- Spring steel
- Stainless steel
- Phosphor bronze
Pros & Cons
Pros
- Compact
- Handles real axial loads
- Standardized sizes (DIN/ASME)
Cons
- Needs pliers and a groove
- Eyes on lugs are fiddly
- Flying rings are a safety hazard
Typical Uses
- Bearings on shafts
- Gears and pulleys
- Bores and housings
- Piston pins
Alternatives & Related
- Snap Ring — The same part in ASME terms
- E-Clip — Push-on retention for light shafts
- Spiral Retaining Ring — 360-degree contact with no lugs
Where to Buy
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FAQ
Circlip vs snap ring?
They are the same component — circlip is the DIN/European term, snap ring the ASME term, for internal and external retaining rings.
Internal vs external circlip?
An external circlip grips a shaft groove and squeezes inward to install; an internal circlip fits a bore groove and expands outward.